Debating the treatment of foreign detainees at Tuesday night's debate, former Massachusetts Gov. Mitt Romney said he thought the US should "double" the number of prisoners held in Guantanamo Bay Cuba.

In the same exchange, former New York Mayor Rudy Giuliani noted again his service in New York following the Sept. 11 attacks and said he would support interrogators using a wide range of means to elicit confessions from suspected terrorists. Moderator Chris Wallace asked if Giuliani would support the use of waterboarding -- a controversial interrogation tactic some say is torture because it makes detainees believe they are drowning.

"Whatever they can think of," Giuliani said.

Romney said suspected terrorists need to be kept off American soil and he supported the use of "enhanced interrogation techniques" with the approval of the president.

Critics say too many detainees are in Guantanamo without trial and some have called for shutting down the facility, Romney noted. A report conducted last year based on an analysis of defense department data found that 55 percent of Guantanamo detainees were not found to have participated in hostilities against the US and only 8 percent were found to be al Qaeda members.

Romney's solution called for ramping up detention efforts at the military base on Cuba's coast.